Transcript Electrical Circuits - Teachnet UK-home

Electrical Circuits
Current in a circuit
Current in a circuit
• Learning objectives:
– At the end of this series of lessons you should be able to use
a model to explain what current is.
Current in a circuit
• An electric current is a flow of charge.
• Electric charge is made up of electrons – tiny
particles that move about in electric wires.
• When a cell or battery is switched ON it gives the
electrons energy so they all move along the wire in
the same direction.
Current in a circuit
• The electrons carry the electrical energy around the
circuit to all the components, which use the energy,
so when the electrons get back to the cell they are
given more energy to go around again.
• Some examples of components are;
– Light bulb
– Buzzer
– Motor
Current in a circuit
• Current is measured with an ammeter.
• The unit of current is the amp (A).
• The size of the current is the rate at which charge is
flowing – if there are more electrons passing by
each second, then the current is larger.
• Current is not used up as it flows around a circuit.
Current in a circuit
• As the electrons pass through a cell they are given
energy.
• The higher the voltage of a cell the more energy it
gives to the electrons.
• Voltage is measured using a voltmeter.
• The unit of voltage is the volt (V).
• As the electrons flow around a circuit they give
away the energy to the components so it can be
changed into other forms of energy like light.